The present disclosure relates to a color converter, a color conversion method, and a non-transitory computer-readable recording medium capable of storing a color conversion program, for converting an input color value to one of a plurality of representative color values and using the converted color value as a printing color value for a printing device.
In recent years, energy conservation has been considered important for ecology and cost reduction. To achieve energy conservation, image forming apparatuses, such as copiers and printers, convert input images to images composed only of representative color values for printing such as single-colored printing and two-color printing.
In the case of converting an input image to an image composed only of representative color values and outputting the resulting image, a known technique is that color values of pixels of the input image are converted to representative color values closest to color values in an RGB color space or a CMYK color space. In this technique, however, the RGB color space and the CMYK color space depend on an output device of an image, and thus, an actually output image varies among output devices, disadvantageously.
In a known technique for solving this problem, color values of pixels of an input image are converted from color values on an RGB color space or a CMYK color space to color values on a device-independent Lab color space expressed by human sense, and then, the resulting color values are converted to closest representative color values on the Lab color space. In this technique, however, in conversion of color values of pixels to closest representative color values, the distance to all the representative color values are obtained for color values of pixels of an input value and the representative color values at the closest distance are used as color values of the pixels after the conversion, and thus, there arises a problem that a large processing amount and a long processing time are necessary for conversion.
In a known technique for solving the problem, color values of pixels, i.e., representative color values that are closest to input color values in a Voronoi diagram are determined as printing color values for a printing device.